One of the problems associated with the manufacture of color cathode ray tubes is crossover of the electron beams emitted from the electron guns as exhibited on the viewing screen of the color cathode ray tubes. Frequently, this crossover condition is due to errors in mounting the electron guns within the envelope of the cathode ray tube. In other words, it is not infrequent to find that the electron guns are mounted within the envelope at a positional location which is either slightly above or slightly below the horizontal axis as seen on the viewing screen.
Other causes of an undesired electron beam crossover condition are rotation of the electron guns within the envelope with respect to the horizontal axis, non-concentricity between the front and back openings of the associated deflection yoke, or undesired variations in the wire positional locations on the deflection yoke associated with the color cathode ray tube. Thus, for any one of the above-mentioned and numerous other conditions the electron beams tend to separate as horizontal deflection or scanning takes place and the phenomenon of crossover is undesirably encountered.
Additionally, it should be noted that this crossover condition is particularly significant for the in-line type of color cathode ray tube wherein all of the electron guns are aligned in a single plane. Also, as is well known, the horizontal deflection windings of toroid-wound deflection yokes are centered on and extend above and below the horizontal axis of the color cathode ray tube while the horizontal deflection windings of basket-wound deflection yokes are disposed above and below the horizontal axis of the color cathode ray tube. Thus, the basket-wound deflection yoke may be electrically altered to compensate for a high or low planar alignment of the electron guns by varying the energy applied to either one of the windings. However, such a feature is not readily available in the toroid-wound deflection yoke since both horizontal deflection windings are centered at and extend above and below the horizontal axis.